package com.atguigu.gulimall.product.service.impl;

import org.springframework.stereotype.Service;

import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        //1.查出所有分类
        List<CategoryEntity> entities = baseMapper.selectList(null);

        //2.组装成父子的树形结构

        //2.1找到所有的一级分类(父节点是0的就是一级分类)
        List<CategoryEntity> Level1Menus = entities.stream().filter(
            //筛选(过滤)出所有的父节点
            categoryEntity -> categoryEntity.getParentCid() == 0
        ).map((menu) -> {
            //map将stream流中的元素变成其它形态。
            //这里我们把每个节点的子节点算出来然后放回去
            menu.setChildren(getChildrens(menu, entities));
            return menu;
        }).sorted(Comparator.comparingInt(menu -> (menu.getSort() == null ? 0 : menu.getSort()))
        ).collect(Collectors.toList());

        return Level1Menus;
    }

    @Override
    public void removeMenuByIds(List<Long> asList) {
        //TODO 检查当前删除的菜单，是否被别的地方引用

        //逻辑删除
        baseMapper.deleteBatchIds(asList);
    }

    private List<CategoryEntity> getChildrens(CategoryEntity root, List<CategoryEntity> all) {
        //找到子菜单
        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid() == root.getCatId();
        }).map(categoryEntity -> {
            //找到子菜单的递归方法
            categoryEntity.setChildren(getChildrens(categoryEntity, all));
            return categoryEntity;
        }).sorted(Comparator.comparingInt(menu -> (menu.getSort() == null ? 0 : menu.getSort()))
        ).collect(Collectors.toList());

        return children;
    }
}